During the Klondike gold rush, inventor Leviticus Blue created a machine to mine through Alaska's ice. The Boneshaker's first test was a catastrophe that destroyed several blocks of downtown Seattle and uncovered a subterranean vein of gas that turned those who breathed it into zombies. Sixteen years later, Blue's widow, Briar, and her teen son, Ezekiel, are surviving beyond the walled-in, toxic portion of the city. Then Ezekiel hatches a plan that takes him under the wall and into the dangerous domain of the undead. Only his mother can bring him back alive.